Automatically configurable computer network

ABSTRACT

A programmably configurable computer network, particularly applicable to small network applications such as home networks, includes a plurality of nodes which may be implemented through wall-box sized components. The nodes may be connected through telephone wires and may also offer telephone connectors at each node. The system may be powered by a high frequency power supply which is isolated from the external telephone system using a low pass filter. In this way, the network can be automatically configured to achieve an efficient and specification compliant topology without requiring rewiring of the building.

BACKGROUND

This invention relates generally to computer networks and particularlyto networks with a relatively small number of nodes.

Computer networks connect computers and other devices together so thatvarious computers on the network can share files, programs andresources. For example, it may be desirable to centralize files on onecomputer and allow access through the network from other computers. Inaddition, it may be desirable to share resources such as a printer witha number of computers. All of these functions can be achieved throughcomputer networks. As a result of the advantages of computer networks,home computer networks are becoming more prevalent. Many homes have morethan one computer and, for the reasons described above, many users wouldlike to share resources and files among those computers.

Today, some builders provide houses which are pre-wired for suchcomputer network connections. The homeowner merely plugs in the variouscomponents into pre-wired wall jacks. However, these pre-wiredconnections tend to be cost prohibitive for most homeowners.

Networks generally come in two basic types. The most common type usestwisted pair cables and includes what is known as a network hub. The hubincludes a plurality of cable connectors so that each computer on thenetwork may be connected to the hub. Some networks use coaxial cableswhere the cable goes directly from computer to computer without using anetwork hub.

The Ethernet is a standardized way of connecting computers into anetwork. The standards for the Ethernet are set forth in the Instituteof Electrical and Electronics Engineers (New York, N.Y.) IEEE 802.3standard. Most common Ethernet systems today transmit data at a rate of10 million bits per second. A newer Ethernet version called FastEthernet has a bandwidth of 100 million bits per second and is sometimesreferred to as 100BaseT. The 10 million bits per second networks aregenerally called 10BaseT when twisted pair cabling is utilized.

A popular network cable is unshielded twisted pair cable (UTP).Generally, UTP cable connects the Ethernet network by coupling thecomputers in a star arrangement. At the center of the star is the hub.UTP cable is generally connected to various devices such as computersthrough UTP connectors called RJ-45 connectors. The RJ-45 connectors aresimilar to the plug-in connectors used to connect telephones (which arecalled RJ-11 connectors).

There are a variety of rules for Ethernet connections compliant with theIEEE standard. One of the basic rules is that there may not be more thanthree hops. A hop is a connection from one device to another. Inaddition, there are rules with respect to the maximum length of cable.For 10BaseT cable, the maximum length is generally 100 meters. Thisnormally means that about 90 meter runs may be used between nodesassuming 10 meter cables are used to connect a computer or other deviceto an RJ-45 connector.

While network technology has been applied widely to larger businesses,the cost has been prohibitive in many cases as applied to home and smallbusiness applications. A large component of the cost associated withhome networks is the need to rewire existing homes to provide theEthernet connections. Normally, this involves using UTP cabling andRJ-45 connectors to provide a plurality of connection points indifferent rooms of the house. These connection points are then wiredtogether using the UTP cable to form the network. Usually, in a 10BaseTsystem, the network would also include a hub.

For existing homes, the wiring expense alone is prohibitive, and evenfor new homes, the expense is sufficiently great that new homes commonlydo not include network wiring.

Thus, there is a continuing need for a network system that avoids theneed for extensive rewiring or special network wiring.

SUMMARY

In accordance with one aspect, a computer network includes a pluralityof nodes. A programmable switching network allows the nodes to beconnected in a plurality of different ways.

In accordance with another aspect, a computer network includes aplurality of nodes connected to telephone lines. Telephone wires connectthe various nodes to one another. A high frequency power supply for thenodes is connected to those telephone wires. However, a filter isarranged to isolate the network power supply from the external telephoneservice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of one embodiment of a node in accordance withone embodiment of the present invention;

FIG. 2 is a flow diagram for the power-up sequence for themicrocontroller shown in FIG. 1;

FIG. 3 is a flow diagram for implementing network configuration rulesfor the microcontroller shown in FIG. 1;

FIG. 4 shows an exemplary connection between a plurality of nodes inaccordance with one aspect of the present invention;

FIG. 5 shows another exemplary connection between a plurality of nodesin accordance with one embodiment of the present invention;

FIG. 6 shows a perspective view of a cutaway building showing theconnections to a plurality of devices connected by a network inaccordance with one aspect of the present invention;

FIG. 7 is a perspective view of the rear of a connector plateimplementing the node shown in FIG. 1; and

FIG. 8 is a front elevational view of the connector plate shown in FIG.5.

DETAILED DESCRIPTION

A programmably configurable node 10, shown in FIG. 1, for a computernetwork includes network connectors 24 a and 24 b and a telephoneconnector 11. The network connectors 24 may be conventional RJ-45connectors used in a UTP system. The telephone connector 11 connects tothe phone line 14 through a low pass filter 12.

The low pass filter 12 prevents the high frequency signal that isdeveloped by the power supply 16 from affecting telephone equipment. Thepower supply provides a DC signal for the microcontroller 18 and theanalog switching matrix 22. Only one node 10 needs to be connected tosystem power as illustrated in FIG. 1. The other nodes may receive powerthrough the node connected to system power.

The microcontroller 18 controls an analog switching matrix 22 which isconnected to the network uplink pair 34 and the network downlink pair36. These pairs may also be referred to as the receive (R+, R−) andtransmit (T+, T−) pairs. Switching matrix 22 also connects the networkconnectors 24 a and 24 b which, in the illustrated embodiment, are RJ-45connectors. The microcontroller 18 drives a plurality of indicators 20associated with each of the connectors 11 and 24 to indicate theirstatus. Additional indicators can be provided as well. The switchingnetwork 22 may also connect to a plurality of transceivers 26 which inturn are coupled by a bus 30.

The microcontroller 18 controls the configuration of the switchingmatrix 22 to provide a programmably configurable node. The node may beconfigured, for example, as a pass through node which simply passes anyinformation it receives on to the next node in the network. In suchcase, the transceivers 26 are not utilized.

The switching matrix 22 may, however, configure the transceivers 26 toprovide a plurality of programmable ports 10. For example, through thetransceivers 26, the node 10 may act as a hub. A plurality of devicescan be connected through the transceivers 26 as desired.

Referring to FIG. 2, upon power-on or after a reconfiguration order tothe node 10, the node 10 checks each transceiver 26 port, checks itsstatus and creates a network map, as indicated in block 64. Next, acheck is made to determine whether there is more than one connection tothe node, as indicated in diamond 66. If so, the network maps from alldownstream nodes are collected and consolidated into one map, asindicated in block 68. The flow waits until all other nodes havereported. The node only sends its local network map upstream, asindicated at block 66. Otherwise the node receives maps from downstreamnodes and only then sends its map to upstream nodes.

In block 72, the node receives upstream network maps, which the nodeconsolidates. The consolidated map is then sent downstream (block 74).The appropriate network configuration rules are then applied to thenetwork map as shown in block 76. The rules could implement, forexample, the IEEE 802.3 standard.

Generally, all of the nodes apply the same rules and should deduce thesame configuration for the network. However, in some cases, it may bedesirable to denominate one microcontroller in one hub as the master andother microcontrollers in other hubs as slaves to that master.

The simple network management protocol (SNMP) may enable various hubs tobe interrogated as to their current condition and the condition of anyresources connected to those hubs. The SNMP describes how information isexchanged those hubs. The SNMP describes how information is exchangedbetween various network devices. Thus, not only may devices connected toa given hub have their status evaluated, but hub-to-hub statusevaluations may be accomplished as well.

The network configuration rules may be implemented using the flow shownin FIG. 3. All nodes except the one with system power may initially beenumerated as #0, while the node with system power is enumerated as #1,as indicated in block 78. In the consolidated maps (FIG. 2, block 72),the nodes are numbered successively extending away from the system hub,as indicated in block 80. Priority is given to the nodes on the lowestnumbered local port. Next a check is made (diamond 82) to determine ifthere are more than three hops. If not, the configuration is complete.

If there are more than three hops, the number of hops must be reduced tothree. A first attempt to resolve the excessive number of hops is to letnodes with one or less devices configure themselves as a pass through toa single connector (block 84). A check is made at diamond 86 to see ifthe number of hops still exceeds three. If not the configuration iscomplete.

Otherwise, the flow lets the nodes with no devices and only two nodeconnections configure themselves as a pass through, as shown in block88. Again a check is made, this time a diamond 90, to see if the threehop rule is still violated. If not the configuration is complete.

Otherwise, the user is signaled to move a device. Nodes which have onedevice more than the other nodes indicate by flashing an indicatorassociated with their device ports (block 92). network map. Thus all thenodes know what changes must be made to all the other nodes.

Referring now to FIG. 5, a plurality of nodes 38 are connected togetherin the exemplary fashion shown in FIG. 2. The nodes 38 are connected toone another using conventional telephone cabling. Conventional telephonecable used in homes includes four wire pairs. These wire pairs may beutilized to provide two telephone lines and two lines for providingnetwork interconnections in an in-home system. The illustratedembodiment uses the Ethernet 10BaseT system.

In the configuration shown in FIG. 4, a node 38 c has configured itselfwith one upload port and four standard ports. The node 38 d hasconfigured itself with one upload port and three standard ports throughthe appropriate programming of the transceivers 26. The nodes 38 a, 38 band 38 e are all configured as one upload and two standard ports. Thus,the wiring connections may be dynamically configurable based on theneeds of the system and the rules of the appropriate network such as theIEEE 802.3 standard. These rules may be stored in the memory 19 of themicrocontroller 18.

Referring next to FIG. 5, a network consisting of nodes 38 f through 38j are connected in a generally linear fashion. The network is wired withfive outlets in series. Since the node 38 g does not have computersattached to it, it has configured itself as a pass through node in ordernot to exceed the 10BaseT hop limits. As indicated by the indicators 20a and 20 c, the network connections of the node 38 g have beendeactivated.

A house 40 may be provided with a network shown in FIG. 6, using aplurality of nodes 38 k through 38 n. Each of these nodes may be formedby the circuitry shown in FIG. 1 within a standard wall electrical box.In the illustrated embodiment, a telephone 41 is connected to the node38 k together with a printer 42. Computers 44 a and 44 b are connectedto the nodes 38 l and 38 m respectively.

A box unit 52, illustrated in FIG. 7, for housing a node 38, includes acover plate 54 and a housing 56. The housing 56 contains the circuitryshown in FIG. 1 and provides a plurality of connections 60 to thetelephone pairs. The cover plate 54 also includes an opening 58 forsecuring the box 52 to the wall.

After the appropriate connections have been made to the telephone pairs,the box 52 is secured to the wall using standard fasteners in theopening 58 so that the cover plate 54 faces outwardly, as illustrated inFIG. 8. The cover plate 54 then provides two network connection plugs,24 a and 24b, and a telephone connection plug 11. These connection plugsmay be labeled as indicated to prevent confusion. Indicators 20 a, 20 b,and 20 c, which may be conventional light emitting diodes (LED), may beprovided to give status information with respect to each of theconnectors 24 or 11.

Each node 10 may also include packet regeneration, automatic polaritydetection/correction and the IEEE defined link integrity test functionwhich continually monitors the receive pair to assure link continuity.In addition, each node may include segment partitioning and jabberlock-up protection.

Using as few as three phone line pairs, two to four local area network(LAN) devices may be connected using standard connectors. The nodes donot require any local power supply. Instead, they are supplied withoperating power from a high frequency signal applied to the primaryphone line either at the phone junction box, at one of the nodes, orwithin the wall. The power supply may be isolated from the telephonecompany lines at the utility box via a low-pass filter.

Through the use of the microcontrollers 18, the network can beautomatically configured to achieve the most desirable topologyconsistent with the applicable standards. When power is supplied, eachnode communicates with each adjacent node to develop a connectiontopology. Then, the nodes plan a topology which meets the restrictionsof any applicable standards. Each node can configure itself as a passthrough, repeater or hub. Further, each port on each node can beconfigured as a standard uplink or pass through port as well asreconfiguring its polarity.

Although the present invention has been described with respect to a10BaseT system, the concepts set forth herein are also applicable toother network connections and to higher throughput Ethernet connectionsas well.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art will appreciate numerousmodifications and variations therefrom. It is intended that the appendedclaims cover all such modifications and variations as fall within thetrue spirit and scope of the present invention.

What is claimed is:
 1. A node for a computer network comprising: ahousing to mount in a wall opening; a programmable switch matrix toallow the node to connect to other nodes in a plurality of differentways; and a memory storing a connection rule that not more than threehops may be coupled to any one node; and a device to insure that thenetwork is automatically reconfigured if the network does not complywith said rule.
 2. The node of claim 1 wherein said switching network isselectively able to allow a node to be connected either as a passthrough node or as a non-pass through node.
 3. The node of claim 1wherein said node is connectable by telephone wires to other nodes. 4.The node of claim 3 including a device that produces a high frequencysignal and a low pass filter to prevent said high frequency signal frominterfering with telephone service.
 5. The node of claim 1 including amicrocontroller, and a plurality of transceivers, and an uplink pair anda downlink pair, said switching matrix selectively connectable to aplurality of transceivers or an uplink pair and a downlink pair.
 6. Thenode of claim 1 including at least one telephone connector and onenetwork connector.
 7. The node of claim 6 wherein each of saidconnectors is associated with an indicator, said indicator adapted toindicate the current status of said connector.
 8. The node of claim 1wherein if said network connection rule is violated, the nodeautomatically attempts to reconnect said hops so as to satisfy saidnetwork connection rule.
 9. A node for a computer network comprising: ahousing to mount in a wall opening; a programmable switching matrix toallow the node to connect to other nodes in a plurality of differentways; and a memory storing a connection rule with respect to how thenodes may be connected, the node automatically attempting to reconfigureitself if the rule is not satisfied, and if the node is unable toreconfigure itself to comply with the rule, the node automaticallygenerates a notification.
 10. The node of claim 9 wherein said rule is arule that not more than three hops may be coupled to any one node. 11.The node of claim 10 wherein if said network connection rule isviolated, the node automatically attempts to reconnect said hops so asto satisfy said network connection rule.
 12. A node for a computernetwork comprising; a housing to mount in a wall opening; a programmableswitch matrix to allow the node to connect to other nodes in a pluralityof different ways; and a memory stroring a connection rule that not morethan three hops may be coupled to any one node, wherein if said networkconnection rule is violated, the node automatically attempts toreconnect said hops so as to satisfy said network connection rule, andwherein if the node is unable to reconfigure itself to comply with thenetwork connection rule, the node automatically generates anotification.